public function __invoke($data)
{
foreach ($data as $category => $documents) {
foreach ($documents as $index => $document) {
if ($this->documentNormalizer) {
$document = $this->documentNormalizer->normalize($document);
}
$tokens = $this->tokenizer->tokenize($document);
if ($this->tokenNormalizer) {
$tokens = $this->tokenNormalizer->normalize($tokens);
}
$data[$category][$index] = $tokens;
}
}
return $data;
}